Use the document.forms property in JavaScript to get the number of <form> tags in a document.
Example
You can try to run the following code to implement document.forms property in JavaScript.
<!DOCTYPE html>
<html>
<head>
<title>JavaScript Example</title>
</head>
<body>
<h1>Employee Information</h1>
<form>
Name: <input type="text" name="name" value="Amit"><br>
Subject: <input type="text" name="sub" value="Java">
</form>
<h1>Department Information</h1>
<form>
DepartmentID: <input type="text" name="dptid" value="D001"><br>
Dept Name: <input type="text" name="dname" value="Marketing">
</form>
<script>
var num = document.forms.length;
document.write("<br>How many forms? "+num);
</script>
</body>
</html>